BACKGROUND AND OBJECTIVES: Cross Infections (CIs) are considered as a major public health problem worldwide. They cause delay in recovery, increased mortality and morbidity. The purpose of this study is to report the incidence of CIs in our teaching hospital during a 23-month period.MATERIALS AND METHODS: In this descriptive cross-sectional study, 76766 patients from 2009 to 2011 admitted to 17 wards of Imam Reza Hospital in Mashhad were studied for CIs. Patients' age, sex, site of infection, ward of hospitalization and type of microbial infections were collected and analyzed by SPSS 16.0.CONCLUSION: Results of the present study showed that the incidence of CIs was low (i.e.<1%) in our hospital and Acinetobacter (25.8%, n = 176) was the most frequent pathogen.